The invention relates to an adjusting mechanism for adjusting the phase relationship between a camshaft and a crankshaft driving the camshaft.
It is known in motor vehicles to utilize variable valve control to optimize fuel consumption and engine performance. For this purpose, for example, the actuation of inlet and outlet valves is varied as a function of engine operating conditions. In engines, a camshaft is gear-driven by a crankshaft via a drive belt or chain, either of which extends around gears of an intake and/or exhaust camshaft and a crankshaft operating the intake and exhaust valves. To vary the valve actuation, it is possible for example to vary the phase position of one camshaft relative to the crankshaft or relative to the other camshaft. Such arrangements for adjusting the phase position conventionally require a relatively large amount of installation space, which is difficult to provide in modern vehicles in which a plurality of units are arranged. In addition, the scarcely available installation space is further restricted by the increasing demands for passive vehicle safety.
An adjusting mechanism is known from the disclosure DE 100 06 365 A1, said adjusting mechanism being formed by planetary gear sets whose elements are concentrated substantially axially on two camshafts which are connected by means of the adjusting drive. Here, one drive wheel drives a first camshaft of the adjusting mechanism via a traction means, said first camshaft then driving a further camshaft which is also part of the adjusting mechanism. The drive wheel also drives a third camshaft which is not connected to the adjusting mechanism.
It is the principle object of the present invention to provide as compact an adjusting mechanism as possible for a camshaft drive arrangement.